Brake beams are well known to those in the art and have been used with railroad car trucks for at least ninety years.
One such brake beam is disclosed in U.S. Pat. No. 2,517,747 of L. L. Whitney, which is assigned to American Steel Foundries of Chicago, Ill.; the entire description of this patent is hereby incorporated by reference into this specification.
This Whitney patent describes a hanger type brake beam comprising a compression member having top and bottom webs and a front web, a filler block externally of the space between said top and bottom webs, bearing against the forward surface of said front web and having an arcuate opening extending from the inboard to the outboard end of said block, a tension member of uniform cross-section from end to end thereof having an end portion bent approximately parallel to said front web, said portion being snugly fitted in said opening, a brake head having a cavity receiving said block, said portion and said webs, said break head having top and bottom rear walls connected to said top and bottom webs, said block and said portion, said connection extending lengthwise of said front web and being spaced from but extending adjacent to the inboard and outboard ends of the block.
The structure of the Whitney patent, in addition to being relatively heavy and cumbersome, provides relatively poor static strength and fatigue strength properties in use.
Another prior art brake beam of hangerless or unit type design is disclosed in U.S. Pat. No. 2,170,121 of C. R. Busch; the entire disclosure of this patent is also hereby incorporated by reference into this specification. This patent discloses a brake beam, including a channel section forming a compression member having its greatest depth at its middle portion, and which, toward its ends, gradually tapers down, and a tension member having its ends firmly attached to the ends of the compression member, the attached ends of the members all extending beyond the points of location for brake heads to guide the beam on car truck frames.
The brake bream device of this Busch patent also is relatively heavy and, per unit weight, provides relatively poor static strength and fatigue resistance properties.
By way of further illustration, other United States patents have disclosed various brake beam designs; none of them, however, have provided a unit brake beam with substantially improved static strength and fatigue strength properties per unit weight. Thus, illustrative of these prior art failed designs are the structures disclosed in U.S. Pat. No. 2,427,548 (integral brake beam with cruciform cross section), U.S. Pat. No. 2,499,905 (brake beam with integral truss and brake heads), U.S. Pat. No. 2,170,122 (brake beam with built-up compression and tension members), U.S. Pat. No. 2,193,580 (brake bream with broad surface for saddle of brake beam strut), and the like. The disclosures of these patents are also incorporated by reference into this specification.
It is an object of this invention to provide a brake beam structure which is relatively light weight but, also, has relatively high static strength and fatigue resistance properties.
It is another object of this invention to provide a brake bream structure which is substantially more durable and less likely to self-destruct during use than comparable multi-piece prior art brake beam devices.
It is another object of this invention to provide a brake beam structure which is greatly simplified and substantially easier to manufacture than prior art assemblies.
It is yet another object of this invention to provide a novel process for producing the brake bream structure of the invention.